LookUpEditBase.ProcessNewValue Event

Occurs when a new value entered into the edit box is validated.

Namespace: DevExpress.XtraEditors

Assembly: DevExpress.XtraEditors.v20.2.dll

NuGet Package: DevExpress.Win.Navigation

Declaration

C#

[DXCategory("Events")]
public event ProcessNewValueEventHandler ProcessNewValue

VB.NET

<DXCategory("Events")>
Public Event ProcessNewValue As ProcessNewValueEventHandler

Event Data

The ProcessNewValue event's data class is ProcessNewValueEventArgs. The following properties provide information specific to this event:

Property	Description
DisplayValue	Gets or sets the value entered by the end-user.
Handled	Gets or sets a value specifying whether the lookup editor must locate the newly inserted record.

Remarks

The editor’s ProcessNewValue event is equivalent to the RepositoryItemLookUpEditBase.ProcessNewValue event available via the LookUpEditBase.Properties object, i.e. adding/removing an event handler for the current event actually affects the RepositoryItemLookUpEditBase.ProcessNewValue event.

Refer to the RepositoryItemLookUpEditBase.ProcessNewValue topic for more information.

Example

Suppose a lookup editor displays a list of persons in the dropdown window. Dropdown rows are retrieved from a collection of a custom ContactList class. For this purpose, the RepositoryItemLookUpEditBase.DataSource property is set to an instance of the ContactList collection.

Each element in the collection represents an object of the Contact class.

The following LookUpEditBase.ProcessNewValue event handler adds new records to the data source. This occurs when the end-user enters a new name in the edit box that does not exist in the dropdown list and presses the Enter key. The entry is added by the Add method implemented in the ContactList class. The ProcessNewValueEventArgs.Handled parameter is set to true in order to force the editor to locate the newly inserted record after the event handler is performed.

Before inserting a new record, a message box is displayed and this allows the user to submit or discard the value. The following message box appears when a ‘Jack Cooper’ entry is entered:

After pressing the ‘Yes’ button, the new string is added to the list and the editor picks it up:

C#

using DevExpress.XtraEditors;
using DevExpress.XtraEditors.Controls;

//ProcessNewValue event handler
void LookUpEdit1_ProcessNewValue(object sender, ProcessNewValueEventArgs e) {
    if ((string)e.DisplayValue != String.Empty && MessageBox.Show(
        this, "Add the '" + e.DisplayValue.ToString() + "' entry to the list?",
        "Confirm", MessageBoxButtons.YesNo) == DialogResult.Yes) {
            ContactList list = (sender as LookUpEdit).Properties.DataSource as ContactList;
            list.Add(new Contact(list.Count, e.DisplayValue.ToString()));
            e.Handled = true;
    }
}

private void Form1_Load(object sender, EventArgs e) {
    //create a contact list 
    ContactList cList = new ContactList();
    cList.Add(new Contact(0, "John Doe"));
    cList.Add(new Contact(1, "Sam Hill"));
    cList.Add(new Contact(2, "Karen Holmes"));
    cList.Add(new Contact(3, "Bobbie Valentine"));
    cList.Add(new Contact(4, "Frank Frankson"));

    //bind the lookup editor to the list
    lookUpEdit1.Properties.DataSource = cList;
    lookUpEdit1.Properties.DisplayMember = "Name";
    lookUpEdit1.Properties.ValueMember = "Id";
    // Add columns.
    // The ID column is populated 
    // via the GetNotInListValue event (not listed in the example).
    lookUpEdit1.Properties.Columns.Add(new LookUpColumnInfo("Id", "ID", 20));
    lookUpEdit1.Properties.Columns.Add(new LookUpColumnInfo("Name", "Name", 80));
    //enable text editing
    lookUpEdit1.Properties.TextEditStyle = TextEditStyles.Standard;
}

public class ContactList : System.Collections.CollectionBase {
    public Contact this[int index] {
        get { return (Contact)(List[index]); }
        set { List[index] = value; }
    }

    public int Add(Contact value) {
        return List.Add(value);
    }
    //...
}

public class Contact {
    private string name;
    private int id;

    public Contact(int _id, string _name) {
        id = _id;
        name = _name;
    }

    public string Name {
        get { return name; }
        set { name = value; }
    }

    public int Id {
        get { return id; }
        set { id = value; }
    }
}

VB.NET

Imports DevExpress.XtraEditors
Imports DevExpress.XtraEditors.Controls

'ProcessNewValue event handler
Private Sub LookUpEdit1_ProcessNewValue(ByVal sender As Object, ByVal e As ProcessNewValueEventArgs)
    If CStr(e.DisplayValue) <> String.Empty AndAlso MessageBox.Show(Me, "Add the '" & e.DisplayValue.ToString() & "' entry to the list?", "Confirm", MessageBoxButtons.YesNo) = DialogResult.Yes Then
            Dim list As ContactList = TryCast((TryCast(sender, LookUpEdit)).Properties.DataSource, ContactList)
            list.Add(New Contact(list.Count, e.DisplayValue.ToString()))
            e.Handled = True
    End If
End Sub

Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)
    'create a contact list 
    Dim cList As New ContactList()
    cList.Add(New Contact(0, "John Doe"))
    cList.Add(New Contact(1, "Sam Hill"))
    cList.Add(New Contact(2, "Karen Holmes"))
    cList.Add(New Contact(3, "Bobbie Valentine"))
    cList.Add(New Contact(4, "Frank Frankson"))

    'bind the lookup editor to the list
    lookUpEdit1.Properties.DataSource = cList
    lookUpEdit1.Properties.DisplayMember = "Name"
    lookUpEdit1.Properties.ValueMember = "Id"
    ' Add columns.
    ' The ID column is populated 
    ' via the GetNotInListValue event (not listed in the example).
    lookUpEdit1.Properties.Columns.Add(New LookUpColumnInfo("Id", "ID", 20))
    lookUpEdit1.Properties.Columns.Add(New LookUpColumnInfo("Name", "Name", 80))
    'enable text editing
    lookUpEdit1.Properties.TextEditStyle = TextEditStyles.Standard
End Sub

Public Class ContactList
    Inherits System.Collections.CollectionBase

    Default Public Property Item(ByVal index As Integer) As Contact
        Get
            Return DirectCast(List(index), Contact)
        End Get
        Set(ByVal value As Contact)
            List(index) = value
        End Set
    End Property

    Public Function Add(ByVal value As Contact) As Integer
        Return List.Add(value)
    End Function
    '...
End Class

Public Class Contact
'INSTANT VB NOTE: The variable name was renamed since Visual Basic does not allow variables and other class members to have the same name:
    Private name_Renamed As String
'INSTANT VB NOTE: The variable id was renamed since Visual Basic does not allow variables and other class members to have the same name:
    Private id_Renamed As Integer

    Public Sub New(ByVal _id As Integer, ByVal _name As String)
        id_Renamed = _id
        name_Renamed = _name
    End Sub

    Public Property Name() As String
        Get
            Return name_Renamed
        End Get
        Set(ByVal value As String)
            name_Renamed = value
        End Set
    End Property

    Public Property Id() As Integer
        Get
            Return id_Renamed
        End Get
        Set(ByVal value As Integer)
            id_Renamed = value
        End Set
    End Property
End Class

Related GitHub Examples

The following code snippets (auto-collected from DevExpress Examples) contain references to the ProcessNewValue event.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

how-to-make-a-lookup-editor-function-as-a-regular-combobox-e2297/CS/MyDataSourceWrapper/MyGridLookupDataSourceHelper.cs#L30

edit.Properties.View.CustomRowFilter += View_CustomRowFilter;
edit.ProcessNewValue += edit_ProcessNewValue;
edit.Properties.View.RefreshData();

lookup-editors-combobox-mode-t378371/CS/Lookup-ComboboxMode/Form1.cs#L60

gridLookUpEdit1.Properties.DisplayMember = gridLookUpEdit1.Properties.ValueMember;
gridLookUpEdit1.ProcessNewValue += GridLookUpEdit1_ProcessNewValue;

VB.NET

how-to-make-a-lookup-editor-function-as-a-regular-combobox-e2297/VB/MyDataSourceWrapper/MyGridLookupDataSourceHelper.vb#L28

AddHandler edit.Properties.View.CustomRowFilter, AddressOf View_CustomRowFilter
AddHandler edit.ProcessNewValue, AddressOf edit_ProcessNewValue
edit.Properties.View.RefreshData()

lookup-editors-combobox-mode-t378371/VB/Lookup-ComboboxMode/Form1.vb#L61

gridLookUpEdit1.Properties.DisplayMember = gridLookUpEdit1.Properties.ValueMember
AddHandler gridLookUpEdit1.ProcessNewValue, AddressOf GridLookUpEdit1_ProcessNewValue